Field of the Invention
The present invention relates to an accessory such as an interchangeable lens that is detachably attachable to digital cameras, and particularly to an accessory having a function of displaying information on image capturing.
Description of the Related Art
Interchangeable lenses include one provided with a display element such as an LCD panel that electrically displays information on an image capturing distance (object distance), a focal length, an aperture value, a depth of field and others. Japanese Patent Laid-Open No. 2007-072407 discloses an interchangeable lens having on its lens barrel a display element such as an electronic paper and displaying thereon information on one of an object distance, a focal length and others selected by operations of a setting switch provided in a camera. In general, such a display element provided in the interchangeable lens starts display of the information in response to turning on of a power switch of a camera and ends the display in response to turning off of the power switch.
However, most digital cameras to which interchangeable lenses are attachable have various selectable (settable) image capturing modes. Digital single-lens reflex cameras have an image capturing mode for performing still image capturing using an optical viewfinder, an image capturing mode for performing still image capturing while displaying a live view image on an electronic monitor provided on a back face of the camera, an image capturing mode for performing moving image capturing and others. Furthermore, an interchangeable lens attachable to the digital single-lens reflex camera is attachable also to a digital mirror-less camera having no optical viewfinder.
In a case where the interchangeable lens is attached to the camera having the selectable image capturing modes or the cameras of different types as described above, switching on and off of the display of the information on the display element in the interchangeable lens in response to the turning on and off of the power switch of the camera wastes electric power.